In the past, a variety of climbing devices and support structures have been developed for use by hunters, naturalists and others having a need to ascend a columnar member, such as a tree or a pole, and then remain there for a given period of time. Initially, such devices and structures were designed for generally permanent attachment to the columnar member. These early devices and structures were not only time consuming to construct, but were also difficult to remove due to their generally permanent attachment to the columnar member.
The subsequent development of portable climbing devices and support structures, such as those disclosed in U.S. Pat. Nos. 4,230,203; 4,553,634; 4,595,079; 4,830,143; 4,909,353; 4,921,069; 5,052,516 and 5,078,232, was in response to the need to ascend a plurality of columnar members located at different locations. A characteristic common to all of these portable climbing devices and support structures is their removable attachment to the columnar members.
While many different types of mechanisms have been proposed for removably attaching the above-described portable climbing devices and support structures, one type of attachment mechanism involves loosely strapping the climbing device or support structure to a tree or pole using a chain and then employing a lever-action mechanism or a cam-action mechanism to tighten the chain (see, for instance, U.S. Pat. Nos. 4,411,335; 4,600,081; 4,730,700 and 5,009,285). While such lever-action and cam-action mechanisms may function effectively to secure their associated climbing device and/or support structure to a columnar member, they are susceptible to inadvertent disengagement, thereby presenting a potential hazard to a user.